Abstract: AIM: To investigate the association of dopamine D2 receptor (DRD2) and 5-hydroxytryptamine 2A receptor (5-HTR2A) gene polymorphisms and their interactions with efficacy of olanzapine in treatment of schizophrenic patients.  METHODS: A total of 147 schizophrenic patients who treated with olanzapine alone were recruited. The positive and negative symptom scale (PANSS) was used to evaluate the efficacy of drugs. According to PANSS reduction rate ≥50% and <50%, patients were divided into the effective group and the ineffective group. The gene polymorphisms of DRD2 (rs1799978, rs1800497) and 5-HTR2A (rs6311, rs6313) were detected by improved multiple ligase detection reaction (iMLDR). Multivariate Logistic regression analysis was used to analyze the correlation between genotypes and olanzapine efficacy, and multifactor dimensionality reduction (MDR) was used to analyze gene-gene interactions. RESULTS: There were significant differences in genotype and allele frequencies of rs1799978 and rs6313 between the effective group and the ineffective group (P<0.05), while there was no difference in genotype and allele frequencies of rs1800497 and rs6311 (P<0.05). Patients with GA and GG of rs1799978 locus were more effective than those with wild type AA when treated with olanzapine, and the ORs (95%CI) were 5.101 (1.118-23.267) and 6.051 (2.454-14.925), respectively. Patients with CT and CC of rs6313 locus were more effective than those with wild type TT when treated with olanzapine, and the ORs (95%CI) were 2.623 (1.054-6.528) and 3.412 (1.180-9.869), respectively. There was a interaction between the gene polymorphisms of rs1799978, rs1800497 and rs6313. The interaction model was the optimal gene-gene interaction model (P<0.05) with the verify sample accuracy rate of 0.727 3 and a cross-validation consistency of 10/10. CONCLUSION: The gene polymorphisms of DRD2 (rs1799978) and 5-HTR2A (rs6313) may be associated with efficacy of olanzapine in treatment of schizophrenic patients, and there is a interaction between DRD2 (rs1799978, rs1800497) and 5-HTR2A (rs6313) on the efficacy of olanzapine.

Key words: schizophrenia, olanzapine, DRD2, 5-HTR2A, gene polymorphism, gene-gene interaction, therapeutic effects